Posted
by
ScuttleMonkey
on Monday March 20, 2006 @06:01PM
from the still-can't-agree-what-real-time-computing-is dept.

BoulderDad writes "LinuxDevices.com is reporting that a proprietary RTOS capable of running Linux binaries has been certified by the FAA as a re-usable software component (RSC). LynuxWorks says LynxOS-178's RSC acceptance will enable greater software reuse among integrators and developers of safety-critical aerospace and defense components."

That seems interesting, but I couldn't find anything to verify. All of those are acronyms. Indeed in government writing, there's an acronym list at the end of every document. Such a list would include WTF (were it used), and AFLA is almost always included as a joke (another four letter acronym).

from dictionary.com:

acronym
n : a word formed from the initial letters of a multi-word name

I think he must be referring to the applications, not the OS itsef. LynxOS is not Linux. It's proprietary real-time OS that can run Linux applications. The LynxOS itself is backed by the vendor, and it's pretty good from what I hear. However, the applications built on it depend on the skill of the application developers, not the OS vendor.

I hope that you weren't implying that LynxOS-178 was "written by the public" -- the summary and the article were both indicated that LynxOS is a proprietary RTOS capable of running binaries compiled for Linux. Despite the name (LynuxWorks), the system is not derived from Linux in any way.

So, what code do you review? And what kernel version? And what happens when there's the next big kernel version jump? How many people and how much time does it take to review all that code?The advantage of an RTOS like LynxOS or Green Hills Integerity, or VxWorks, is that it just works, sure that price sounds pretty big, but compare it to the time of digging through all the code yourself. It is possible to get a version of Linux that could pass DO-178B certification, but it's something else entirerly to

Actaully, certification is all you really have. To obtain OS-178B is very difficult.

Microsoft was approached by my company to get OS-178B. Once they looked at what it would entail, they called back a week later and told us that they had a good laugh. In their own words, not even Vista will come close. And XP was not even a consideration.

Be sure to read the article. This is LynxOS with Linux API on top. That is much easier to do.

But if you check google, you will find that there are several other companies with OS-178B version of Linux. They are a pain to work with as they are nothing but a stripped down redhat with a few re-written parts. Do you think that before I write code for any of these, that I am going to check over all the code? Not one line. I trust that the FAA and the company that sell these did that already. Why do I do that? Because, I do not have the time to do that and write my code.

Just about anything permanently mounted to an aircraft requires FAA approval, most early GPSs were not IFR approved, but now almost all panel mount GPSs have certification for enroute navigation, and many have approval for approach use (on GPS approaches).

I know this for a fact because I had a field inspector yelling at me about a camera mount until I showed him that it was removable, and not a hazard to flight.

Level A software is on the most critical systems, while Level E is non-interference (i.e., if the system fails, it's a minor nuisance, and just needs to be shown that it cannot take out any more critical systems).

You are correct. If it is actually panel mounted, and not "removable", it will be certified to some degree. It maybe just be for "situational awareness" and not connected to any kind of flight guidance or be certified for GPS approaches or even WAAS.

I'm just more familiar with the "handheld" units (Frequently semi-permanently mounted) that aren't certified at all.

Umm, i have a GPS enabled/radio autopilot installed on my boat. It says right on it "not a navigational system" "it is up to the user to ensure proper charts and navigation is being followed"The strange thing is that the reciever and controlers are certified for aviation use with the same warnings. Supposedly this system can be used to control small aircraft with a little different hardware and hookup. Ohh yea, and suprisingly it is reletivly cheap. The control unit and recievers cost around $5,000 us to bu

That is just one part of a total system. Keep in mind that the nav. part that you saw was not connected into anything. All it did was have a self contained GPS and displayed a moving map. To be able to touch ANYTHING beyond the power of an aircraft, requires an OS178B cert. OS. Right now, the company that I work at owns their market (about 98% of all aviation navigation; guess who). Currently, we have a great deal of windows products. But we are in the process of moving them into the cockpit. So we are usin

As others have mentioned, this is a proprietary OS that supports the Linux ABI, not any version of Linux.

I've developed and shipped software certified to DO-178B level A on a likewise certified OS (on two different aircraft), and I can state categorically that no widely-used general purpose OS will ever be certified to that level. The requirements are just way too stringent to apply to anything that wasn't developed from the ground up with the intent of achieving certification. For level A software for

It's not just acronyms. It's mixed units. A METAR in North America (Canada, at least) will get you the temperature in degress Celsius, windspeeds in knots, visibility in statute miles, and cloud bases in feet. (We'll leave the altimeter setting as mmHg as a side issue.)

Of course, TAFs are worse. And lets not forget the shorthand for weather conditions (rain/showers/etc) comes from French.

yes, you gotta love the met speak weather reports. Wonder why that is though, that aviation is so full of acronyms, I have a licence myself and half the theory exams felt like they were just about recognizing acronyms..

oh, and to all you people writing weather applets -- CAVOK doesn't necessarily mean it's going to be sunny, just that the Ceiling And Visibility is above a certain level (and hence deemed OK). It can be completely overcast, just as long as the clouds are high enough.

It's when the plane becomes overcrowded and the OOM Killer starts deleting passengers that take too much room that you might have to be concerned. Or selinux is enabled and the pilot doesn't have the right security label for the brakes...

Back to the LynxOS stuff, though. If LynxOS can run Linux binaries, then people can develop on Linux and run under LynxOS. (Duh!) As the hardware for development is orders of magnitude more expensive than the development tools, I'm not sure it'll have much short-term impact

A non Linux OS that can run Linux software has been approved for use on Aircraft computer systems.

The Linux applications would also need to be certified but a base OS that can handle realtime input (IE dont lag up mouse movement and your MP3's should glitch ever type of OS realtime) and has library compatibility to Linux enabling it to run applications written for Linux has been approved by the powers that be.

Holy run-on confusing sentence with garbled wording and random nonsensical DRM reference with strange out of place parenthesis (that just serve to confuse the sentence even more) in the middle of the already long and mangled run-on, batman!

And a little research turns up per-developer pricing, although not the per-unit run-time license cost. That's not actually unreasonable, given the cost of DO-178B Level A documentation, but still. Ouch.

Price and Availability
In addition to the LynxOS-178 kernel, the offering also includes a complete artifacts package for the kernel and user library, DO-178B required documentation, code coverage test suites and analysis for 100% modified condition/decision coverage of the kernel and libraries, a full suite of standards-based development tools, and support. The company will also soon release the industry's first commercial-off-the-shelf certifiable TCP/IP stack. Development seats, including the LynxOS-178 kernel and one year of priority support, start at $18,000.

And a little research turns up per-developer pricing, although not the per-unit run-time license cost. That's not actually unreasonable, given the cost of DO-178B Level A documentation, but still. Ouch.

Note that, because it's a Linux API, the bulk of the development can be done on Linux platforms WITHOUT per-developer licenses.

You'd need occasional testing against the real OS by someone "sitting in a licensed seat" - to check the behavior under the real OS's scheduling regime and detect reliance on missing or divergent features. And of course you'd have to hammer on it ifn licensed seats (and real or excelently hardware modeled aircraft devices) for final test. But if the licenses are sufficiently dear you concevably might end up ahead. (You wouldn't need per-seat licenses for initial prototyping work, either.)

(The "reliability tested in later" nature of such an effort wouldn't be an extra burden if machines connected to prototype hardware or timing-accurate models of them also aren't available at all seats all the time.)

A lot of software might not need close modeling thoughout development to get right.

I haven't investigated this product, but I think this is "per developer", not a floating seat license.Realistically, when the time comes to do debugging, you wouldn't want fewer seats than developers anyway.

And you're not really running on a PC here. You'd almost certainly be running on proprietary hardware, hooked up to special power supplies, with bizarre aviation hardware interfaces. Each target box might run a substantial fraction of $18k.

IIRC, compared to other aviation & avionics software, that's a bargain. The support there is probably a significant portion of that cost too. Still, peanuts compared to the cost of a coder's time in the aviation industry. I'm not IN the avionics industry, but I know several people that work for a couple such companies.

LynuxWork's press releases are much more impressive than what they actually deliver. My company is trying to use their 178 OS for one of our products. The current version of the 178 OS does not have Linux ABI compatibility. It doesn't even use ELF binaries, it only runs XCOFF, which hasn't been supported by GCC for years. We're stuck with GnuPro 2.95, and are having lots of performance problems. When they gave us the first delivery, they didn't have the cache enabled! The compiler also didn't align fl

Some OS that's able to run Linux binaries might be (rightly) judged as showing that Linux is something to be taken seriously, but I really don't see how this feature makes it "friendly" to Linux. It's a bit like saying Microsoft was being "friendly" to Netscape with the release of Internet Explorer.